I found a way around these, but here they are.
B4X:
Private Sub B4XPage_Created (Root1 As B4XView)
Root = Root1
Root.LoadLayout("1")
TextEngine.Initialize(Root)
TextEngine.TagParser.UrlColor = 0x228b22 'breaks auto underline, except for line4 which has same color as Url color
' the underline is still there (it can be seen in letters such as gjqp) but is the background color (or transparent).
BBCodeView1.TextEngine = TextEngine
'Without line6 the auto underline works only for line1 and line5
'With line6 the auto underline works as expected for all lines
BBCodeView1.Text = _
$"
line1: this is [url]some phrase[/url] and more
line2: this is [url][b]some link2[/b][/url] and more
line3: this is [url]link3[/url] and more
line4: this is [url][color=#228b22]link4[/color][/url] and more
line5: this is [url]some phrase[/url] and more
line6: [Span MinWidth=0%x] [/Span]
"$
End Sub